A Japanese prior-art published patent, JP H11-147699A, discloses a control system for a device that vertically transfers a load. This load-transfer device includes a mechanism for vertically carrying the load, a drive source for driving the mechanism, and a control part and a handling part, for controlling the drive source, and further includes a control system, wherein a sensor provided in the handling part detects the magnitude of the lifting force of an operator created when he or she holds the handling part and pushes the load upward against the gravity, and the hoisting power of the load-transfer device is amplified in response to the magnitude of the lifting force of the operator, thereby vertically moving the load by the amplified hoisting power and the lifting force. That control system in the load-transfer device controls the amount of air to be supplied to a cylinder by always or approximately increasing the ratio of the hoisting power to the lifting force as the lifting force become greater.
When this control system is used, for example, to manually carryout aligning and fitting the bushings of a cope on the pins of a drag for mating them, it is necessary to place the cope, which is suspended by an overhead traveling crane or the like, just above the drag first by depressing or controlling the operating buttons of the control panel of the crane first, and then necessary to lower the cope onto the drag.
On the other hand, there is a power assistance system developed as a research power assistance system for use in factories (as taught in “Development of the Power Assistance System for Transportation” by Hisashi Nakamura, the System Integration Division Science Lecture Meeting '01, Lecture Meeting Thesis Collection 2001, pp. 515-516), where the man's operating physical force (imposed force) is measured by a force sensor to obtain an assistance force (supplementary force) that will correspond to the imposed force. Further, other power assistance systems are known, such as one (as taught in “Trial for Safety of Skill Assistance” by Youji Yamada, the System Integration division Science Lecture Meeting '01, Lecture Meeting Thesis Collection 2001, pp. 519-520), where the skill assistance (technological assistance) is carried out considering not only reducing the burden of the worker but also his or her operational feeling, and the COBOTO (“Cobots for the Automobile Assembly Line” by P Akella, Proc. IEEE Int. Conf. Rob Autom 1999, pp. 728-733), where a man operates the system with an acceleration pedal and a steering wheel.
However, since in the former control system of the device for hoisting the load the instructions for moving the load at a velocity and in a direction are given by handling an operating lever by a operator, which lever is disposed apart from the load, the operator cannot simultaneously hold the load and operates the lever, giving the operator a non-excellent operational feeling when he or she hoists the load. Further, in a cope-and-rag mating operation, the cope sways when it is moved to a position above the drag, causing a difficulty with mating them precisely. Accordingly, the operator had to repeatedly depress the buttons of a control panel to precisely position the cope relative to the drag. This was inefficient. Further since the operator had to operate with his or her both hands simultaneously holding the cope and the control panel, the operation was difficult, causing a problem in that the physical burden on him or her would be great.
Further, since in the latter power assistance system a sensor for measuring the operational physical force imposed on the load by the operator is disposed in a position separated from the load, he or she cannot direct touch the load or cannot feel a response from it when he or she operates to transfer it. Accordingly, an excellent operational feeling is not given. Further, since the power assistance system requires a special-purpose device, it cannot be introduced in the existing overhead traveling cranes used in factories.
Further, since in the control systems for the conventional devices for hoisting a load or the conventional transfer means the instructions for moving the load in a given direction and at a given velocity are to be generated by operating the operation lever by the operator, he or she cannot simultaneously holds the load and operate it, causing a problem in that he or she cannot hoist the load in an excellent operational feeling.
Further, since in a cope-and-drag mating operation, the cope sways when it is moved to a position above the drag, causing a difficulty with mating them precisely and requiring repeated fine adjustments of the position of the cope by depressing the buttons of a control panel many times. This was inefficient. Further since the operator has to operate with his or her both hands simultaneously holding the cope and the control panel, the operation is extremely difficult, causing a problem in that the physical burden on him or her will be great.
Further, there were problems in that the operator cannot hoist the load in an excellent operational feeling, and in that further the operator cannot horizontally move the load, since he or she simultaneously carries out both holding the load and operating the control lever.